1. Field of the Invention
The present invention relates to a status discriminating apparatus of human, animal, machine or the like capable of discriminating normal or abnormal status of human, animal, machine or the like automatically, quickly and accurately by using an ultrasonic vibration detecting sensor, and a status discriminating method of human, animal, machine or the like by using the same, being mainly used in observation of status of inpatients in hospital, and observation of an animal, a machine or the like.
2. Description of the Prior Art
In a hospital or factory, for example, television camera systems are widely used in remote observation of inpatients and machines, and the circumstance in hospital or factory is continuously observed by monitor screens installed in a nurse station or operation room.
Further, the hospital or factory is equipped with nurse call devices, or other communication devices for transmitting the requests of patients, or the condition of machines, to the nurse's station, or operation room, by means of pushbutton operation or microphone operation, and the patients or machine operators can transmit their will freely. Examples of prior art nurse call devices, or communication devices useful for monitoring, are described in the non-patent references listed below.
Non-Patent Reference 1
1) Bio information detection by making use of pressure and acoustic changes of air mat
“Studies in university”
Yoshijiro Watanabe, Assistant Professor, Hosei University Faculty of Engineering, Air mat utilization technology
A Study on Sleep Stage Estimation via Non-invasive Air Mattress
Sensor {SICE Annual Conference 2003 in Fukui}
Non-Patent Reference 2
2) Mat sensor confirming bed-leaving by pressure changes
“Products”
Takenaka Engineering Co., Ltd. Poriomania, bed-leaving alarm
http://www.takex-eng.co.jp/shoukai/index_helth.html
Technos Japan Co., Ltd. Poriomania, bed-leaving alarm
http://www.technosj.co.jp/Fukushi/Haikai/Frame/haikai_top.htm
In such television monitor systems, however, it is hard to discriminate a specific condition of individual patients, or machines, accurately, and it is nearly impossible to judge the breathing condition of severely ill patients in the nighttime.
The problem is the same in the nurse call system, that is, a severely ill patient cannot utilize the nurse call system.
To solve these problems, the present applicant newly developed an ultrasonic vibration detecting sensor completely different in structure and function from the existing accelerometer or vibrometer, and developed a human status measuring method using this ultrasonic vibration detecting sensor, which is disclosed in Japanese patent application Ser. No. 2002-118842.
In this human status measuring apparatus, as shown in FIG. 14, an ultrasonic measuring apparatus composed of an ultrasonic vibration detecting sensor A and an ultrasonic control device B is installed in a bed C, and human status changes (i.e., changes of vibration state) are detected by the ultrasonic vibration detecting sensor A, and analyzed by the ultrasonic control device B, so that normal or abnormal status of the human patient can be discriminated.
The ultrasonic vibration detecting sensor A is, as shown in FIG. 13, composed of a container main body 1, a liquid 2 packed in the container main body 1 so as to have a liquid level in its inside, and an ultrasonic vibrator 3 for transmitting an ultrasonic wave c into the liquid 2 and receiving an ultrasonic wave d reflected from the liquid level (i.e., the liquid surface).
The ultrasonic control device B is for controlling the ultrasonic vibration detecting sensor A so as to transmit and receive the ultrasonic waves c, d from the ultrasonic vibrator 3 into the liquid 2, and it is designed to receive and issue transmission and reception signals a, b through a cable 4, and analyze the input signal b to discriminate the normal or abnormal status of the human.
In the human status measuring method previously proposed by the present applicant, as shown in FIG. 14, the ultrasonic vibration detecting sensor A is installed properly in the bed C, and the ultrasonic control device B is provided for receiving and controlling the ultrasonic wave d reflected from the liquid level 2a by transmitting the ultrasonic wave c into the liquid 2 from the ultrasonic vibrator 3 of the ultrasonic vibration detecting sensor A, so that the human status 5 can be measured by measuring the changes of the liquid level 2a caused by the status of the human 5 by the reflected ultrasonic wave d from the liquid level 2a. 
The explanation in FIG. 14 refers only to human status measurement, but this ultrasonic vibration detecting sensor can be similarly applied in measurement of status of animals, machines, etc.
The human, animal or machine status measuring method by using the ultrasonic vibration detecting sensor A in FIG. 13 and FIG. 14 previously developed by the present applicant is based on the principle of discriminating changes of status of human, animal, machine or the like from the state changes (in particular, amplitude changes) of vibration waveform of reception ultrasonic wave d detected by the ultrasonic vibration detecting sensor A, and life or death of a human or an animal, or damage of a machine can be detected and judged at a relatively high precision. In other words, the human, animal or machine monitoring method described above relies upon the detection of vibration (i.e., movement) generated by the living human or animal, or the operating machine. The absence of vibration generated by a human or animal suggests the creature is dead. Likewise, machines that are no longer operating (i.e., are “dead”) do not generate vibrations.
However, the development is still halfway for quantitative determination means or measures for estimating the degree of risk leading to death of a human or an animal, or the degree of risk of leading to the breakdown of machine, from the reception of ultrasonic signal detected by the ultrasonic vibration detecting sensor A, and there are various problems to be solved until the method has practical use in patients, animals and machines. In particular, in the presence of large background noise or vibration, normal or abnormal status of a human, an animal, a machine or the like cannot be specifically judged at high precision.
In the status measuring method of human, animal, machine or the like previously developed by the present applicant, the ultrasonic control device B is composed of a conventional so-called “discrete circuit,” which is an expensive circuit, and the construction expense of the system for realizing this method is soaring, and it is hard to lower the cost.